1. Field of the Invention
The present invention relates to an apparatus for adjusting or regulating the air pressure within an air support embedded in the seat of a vehicle or car, and an onboard concentrated control system combined with the air support pressure adjusting apparatus.
2. Description of Prior Art
Some cars on the market at present are equipped with air supports incorporated in their seats for improving comfort, together with an associated seat controller, an air conditioner, an audio system, a video system, a telephone and other installations.
The air support, which is essentially an air bag adapted to be controlled by a seat controller, is usually incorporated in the seat cushion and the seat back for improving the comfort of the driver and passengers. More specifically, the air support is disposed at a front end portion of the seat cushion so as to adjust the pressure of the seat cushion at the location where the thigh of the driver or passenger rests and/or in the seat back at a location where the lumbar region is pressed. The air pressure can be set at a value desired by the passenger. Ordinarily, the air pressure is previously set at a desired level by the user so as to assure his or her comfortableness in driving the car.
Heretofore, adjustment or regulation of the air pressure within the seat air support mentioned above is performed through such a procedure as illustrated in a flow chart shown in FIG. 1.
More specifically, several levels of the air pressure to be produced within the air support are previously set on the basis of experimental data and stored in a memory. When a button switch corresponding to the pressure level desired by the user is actuated, the actual or current air pressure value within the air support is detected by appropriate means such as a pressure sensor to be subsequently compared with the corresponding value stored in the memory and selected or designated by the user. In accordance with the result of the comparison, a suction pump as well as a valve associated therewith is operated. Assuming, by way of example, that the detected pressure is higher than that stored in the memory, the air suction pump is operated to discharge the air from the air support, as the result of which the air support pressure is reduced down to a certain level. At that time, the current pressure is again measured and an averaged value thereof (since the pressure representing signal produced by a pressure sensor varies in amplitude, a mean value is determined) is compared with the selected value stored in the memory. When the current pressure is still higher than the stored value, the suction pump is again actuated to further lower the air support pressure. This procedure is repeated until the current air support pressure becomes equal to the selected value stored in the memory, indicating that the desired pressure is actually established, whereupon the suction pump is stopped. On the other hand, when the comparison results in that the stored pressure value is lower than the detected value, a charge pump is actuated to increase the air support pressure. This cycle is usually repeated several times until the desired air support pressure has been actually set at the optimum level.
The hitherto known procedure for producing the desired pressure level stored in the memory is disadvantageous in that a troublesome process is involved in controlling the suction or charge pump. The pump must be selectively actuated in accordance with the measured or detected value, not to say the difficulty encountered in accurately controlling the pumps. Further, much time is required for establishing the desired air support pressure since the pump has to be stopped with the associated valve being closed, every time the pressure measurement is performed.
Besides, control means, such as switches for various onboard equipment mentioned hereinbefore, are discretely installed at various locations such as the instrumentation panel in front of the driver and the sides of seats and the doors. Consequently, to reach the manipulation switches, the operator is necessarily forced to move his or her hand, which often requires the operator to assume unnatural posture.